Exploration summary report Georgie period ending 01-03-1989.

Abstract

A ground magnetic survey was carried out by Solo Geophysics. Readings were taken at a height of 8 feet at 5 metre - intervals along 40 metre spaced grid lines. The contoured results shown in figure 6 and a modelled interpretation in figure 7. There is a distinct zone parallel tothe inferred position of the Mary Lane Shear Zone where the rocks are relatively non magnetic. The boundary of the shear zone has been assumed to be vertical for this model. The high to the south is best modelled as a fold. A reasonable fit can be obtained for the target with a steep south plunge. It has been assumed a 180 degree azimuth for the plunge as there is4 not a clear indication otherwise from the data. The depth to the top is around 50 to 70 metres and the susceptibility used is indicative of an ironstone source. The ground magnetic data indicate a structure between the Hidden Mystery and the broad high to the south. Soils are mostly thin and residual and should reflect accurately the geochemistry of the underlying bedrock. From orientation work carried out elsewhere in the Tennant Creek Field, the optimum size fraction for sampling soils was found to be -180 microns. Samples of this fraction were taken only over MCC's 534 and 535 to date. The samples were collected on a 40 x 20 metre spaced grid and submitted for aqua regia/GTA gold analysis. There were no significant results within the area sampled. A geophysical interpretation was made on the data that was purchased by Metana from Austirex International Limited. An airborne geophysical survey was conducted by Austirex between June & July 1984. The flight lines were spaced by 200 metres, with tie lines separated by 4000 metres. A proton precession magnetometer was used for data collection. This had a resolution of 0.1 nano Tesla, a cycle rate of 0.5 seconds and a sample interval of 30 metres. The interpretation indicates that the lease is located on east west striking magnetic units of the Carraman Formation, The southern block of claims is cut by a splay of the Mary lane Shear Zone. A 'bulls eye 'type magnetic anomaly associated with the Hidden Mystery workings is situated on the western boundary of MCC 531. The area was geologically mapped by D. Tonkin. Mudstones of the Carraman Formation outcrop or subcrop over most of the area. Quartz veining is ubiquitous in these sediments. Ironstone lenses, aligned along the Mary Lane shear zone, consist principally of massive black hematite, micaceous hematite and quartz. Shearing is evident in most places. Most ironstones are weakly to moderately magnetic. Away from the Hidden Mystery workings the ironstones tend to become jasperlitic and more siliceous. Abundant ironstone float is common in many places, possibly reflecting more substantial lenses at depth. Small intrusions of lamprophyre were observed in places, but drilling at the Hidden Mystery workings suggest these may be more common than is evident from surface mapping. Laterite crops out along some stream channels. A limited number of rock chip samples were taken, HMR 1 to HMR The locations are shown on the geology map. The samples were analysed for gold only. Future exploration should include bedrock drilling traverses, to determine the underlying lithology and to investigate the potential for shallow level oxidised or non magnetic mineralisation, especially in the vicinity of the Nary Lane Shear Zone. An angled reverse circulation hole, drilled on either 3320E or 3360E and collared no further south than 2880N is recommended to initially test the magnetic target in the north west of MCC 531.